PreparedPrepared inin cooperationcooperation withwith thethe TexasTexas WaterWater DevelopmentDevelopment BoardBoard TrendsTrends inin SelectedSelected StreamflowStreamflow StatisticsStatistics atat 1919 Long-TermLong-Term Streamflow-GagingStreamflow-Gaging StationsStations IndicativeIndicative ofof OutflowsOutflows fromfrom TexasTexas toto Arkansas,Arkansas, Louisiana,Louisiana, GalvestonGalveston Bay,Bay, andand thethe GulfGulf ofof Mexico,Mexico, 1922–20091922–2009 Scientific Investigations Report 2012–5182 Revised September 2012 U.S. Department of the Interior U.S. Geological Survey Background, Looking towards the right bank of the Sabine River during a flood measurement at stream- flow-gaging station 08030500 - Sabine River near Ruliff, Texas, on October 23, 2006. Photograph by Doug McGhee, U.S. Geological Survey. Front cover: Left, Discharge measurement at streamflow-gaging station 08117500 - San Bernard River near Boling, Texas. Photograph by Mac Cherry, U.S. Geological Survey on April 1, 2007. Right, Gage shelter raised above 200-year flood-plain level at 08114000 - Brazos River at Richmond, Texas, January 15, 2007. Photograph by Joe Stuart, U.S. Geological Survey. Back cover: Left, U.S. Geological Survey streamflow-gaging station 08475000 - Rio Grande near Brownsville, Texas, August 18, 2010. Photograph by Jaimie Ingold, U.S. Geological Survey. Right, Gage shelter and wire-weight gage at 08041000 - Neches River near Evadale, Texas. Photograph by Joe Stuart, November 17, 2006. Trends in Selected Streamflow Statistics at 19 Long-Term Streamflow-Gaging Stations Indicative of Outflows from Texas to Arkansas, Louisiana, Galveston Bay, and the Gulf of Mexico, 1922–2009 By Dana L. Barbie and Loren L. Wehmeyer Prepared in cooperation with the Texas Water Development Board Scientific Investigations Report 2012–5182 Revised September 2012 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2012 Revised 2012 This and other USGS information products are available at http://store.usgs.gov/ U.S. Geological Survey Box 25286, Denver Federal Center Denver, CO 80225 To learn about the USGS and its information products visit http://www.usgs.gov/ 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Barbie, D.L., and Wehmeyer, L.L., 2012, Trends in selected streamflow statistics at 19 long-term streamflow-gaging stations indicative of outflows from Texas to Arkansas, Louisiana, Galveston Bay, and the Gulf of Mexico, 1922–2009: U.S. Geological Survey Scientific Investigations Report 2012–5182, 20 p. (Revised September 2012) iii Contents Abstract ..........................................................................................................................................................1 Introduction ....................................................................................................................................................1 Purpose and Scope .............................................................................................................................1 Description of Study Area ..................................................................................................................3 Previous Studies ..................................................................................................................................3 Methods ..........................................................................................................................................................3 Trends in Selected Streamflow Statistics .................................................................................................6 Outflows to Arkansas (Red and Sulphur River Basins) .................................................................6 Outflows to Louisiana (Little Cypress Creek Basin) .......................................................................8 Outflows to Upper Coast Gulf of Mexico (Sabine and Neches River Basins) ...........................8 Outflows to Gulf of Mexico through Galveston Bay (Trinity and San Jacinto Rivers and Associated Creeks and Bayous) ..........................................................................................9 Outflows to Middle Coast Gulf of Mexico (Brazos, San Bernard, and Colorado River Basins) .........................................................................................................................13 Outflows to Lower Coast Gulf of Mexico (Guadalupe and Nueces River Basins and Rio Grande Basin) ................................................................................................................16 Summary .......................................................................................................................................................19 References ...................................................................................................................................................20 Figures 1. Map showing basin boundaries for major rivers in Texas that outflow to Arkansas, Louisiana, Galveston Bay, and the Gulf of Mexico .................................................................2 2. Map showing statistically-significant trends in the annual mean daily discharge for the period of record through 2009 for streamflow-gaging stations with more than 50 years of record indicative of outflows from Texas ...................................................4 3. Graph showing annual mean daily discharge for the period of record through 2009 for U.S. Geological Survey streamflow-gaging station 07337000 Red River at Index, Arkansas .......................................................................................................................................7 4. Graph showing annual mean daily discharge for the period of record through 2009 for U.S. Geological Survey streamflow-gaging station 08041000 Neches River at Evadale, Texas .......................................................................................................................10 5. Graph showing annual mean daily discharge for the period of record through 2009 for U.S. Geological Survey streamflow-gaging station 08066500 Trinity River at Romayor, Texas ..........................................................................................................................12 6. Graph showing annual mean daily discharge for the period of record through 2009 for U.S. Geological Survey streamflow-gaging station 08073500 Buffalo Bayou near Addicks, Texas ............................................................................................................................14 7. Graph showing annual mean daily discharge for the period of record through 2009 for U.S. Geological Survey streamflow-gaging station 08076000 Greens Bayou near Houston, Texas ..................................................................................................................15 8. Graph showing annual mean daily discharge for the period of record through 2009 for U.S. Geological Survey streamflow-gaging station 08475000 Rio Grande at Brownsville, Texas .....................................................................................................................18 iv Tables 1. Selected U.S. Geological Survey or International Boundary and Water Commission streamflow-gaging stations with more than 50 years of record that were used to assess trends in outflows from Texas to Arkansas, Louisiana, and the Gulf of Mexico .......................................................................................................................5 2. Monotonic trends in outflows from the Red and Sulphur River Basins in Texas, 1937–2009 ......................................................................................................................................6 3. Monotonic trends in outflows from the Little Cypress Creek Basin in Texas, 1947–2009 ......................................................................................................................................8 4. Monotonic trends in outflows from the Sabine and Neches River Basins in Texas, 1925–2009 ......................................................................................................................................9 5. Monotonic trends in outflows from the Trinity and San Jacinto River Basins and associated creeks and bayous to Galveston Bay in Texas, 1925–2009 ............................11 6. Monotonic trends in outflows from the Brazos, San Bernard, and Colorado River Basins in Texas, 1923–2009 ......................................................................................................16 7. Monotonic trends in outflows from the Guadalupe and Nueces River Basins, and the Rio Grande Basin in Texas, 1926–2009 ............................................................................17 Conversion Factors Inch/Pound to SI Multiply By To obtain Length mile (mi) 1.609 kilometer (km) Area square mile (mi2) 2.590 square kilometer (km2) Flow rate cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) Horizontal coordinate information is referenced to the North American